class Counter{
    private static int count = 0;
    public static void add(){
        synchronized (Counter.class){
            count++;
        }

    }

    public static int get(){
        return count;
    }
}
public class ThreadDemo1 {
    public static void main(String[] args) throws InterruptedException{
        Thread t1 = new Thread(() ->{
            for (int i = 0; i < 50000; i++) {
                Counter.add();
            }
        });
        Thread t2 = new Thread(() ->{
            for (int i = 0; i < 50000; i++) {
                Counter.add();
            }
        });
        t1.start();
        t2.start();
        t1.join();
        t2.join();
        System.out.println(Counter.get());
    }
}
